Changes in Equity (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Feb. 28, 2014	Feb. 28, 2013	Feb. 28, 2014	Feb. 28, 2013
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balances - September 1 (Beginning of period)			$ 781,199	$ 1,085,696
Net income (loss)			(2,728)	8,202	[1]
Other comprehensive loss, net of tax			(6,598)	(7,288)	[2]
Distributions to noncontrolling interests			(1,072)	(1,002)
Restricted stock withheld for taxes			(676)	(1,161)
Stock options exercised			240	300
Share-based compensation			7,180	7,156
Excess tax deficiency from stock options exercised and restricted stock units vested			(674)	(852)
Adjustments to fair value of redeemable noncontrolling interest			0	(2,504)
Cash dividends			(10,094)	(9,915)
Balances - February 28 (End of period)	766,777	1,078,632	766,777	1,078,632
Net loss attributable to redeemable noncontrolling interest				903
Foreign currency translation adjustment attributable to redeemable noncontrolling interest	0	(886)	0	(1,059)
Parent [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balances - September 1 (Beginning of period)			776,558	1,080,583
Net income (loss)			(4,440)	6,970
Other comprehensive loss, net of tax			(6,598)	(7,288)	[2]
Distributions to noncontrolling interests			0	0
Restricted stock withheld for taxes			(676)	(1,161)
Stock options exercised			240	300
Share-based compensation			7,180	7,156
Excess tax deficiency from stock options exercised and restricted stock units vested			(674)	(852)
Adjustments to fair value of redeemable noncontrolling interest			0	(2,504)
Cash dividends			(10,094)	(9,915)
Balances - February 28 (End of period)	761,496	1,073,289	761,496	1,073,289
Noncontrolling Interest [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balances - September 1 (Beginning of period)			4,641	5,113
Net income (loss)			1,712	1,232	[1]
Other comprehensive loss, net of tax			0	0	[2]
Distributions to noncontrolling interests			(1,072)	(1,002)
Restricted stock withheld for taxes			0	0
Stock options exercised			0	0
Share-based compensation			0	0
Excess tax deficiency from stock options exercised and restricted stock units vested			0	0
Adjustments to fair value of redeemable noncontrolling interest			0	0
Cash dividends			0	0
Balances - February 28 (End of period)	$ 5,281	$ 5,343	$ 5,281	$ 5,343

[1] Net income attributable to noncontrolling interests for the six months ended February 28, 2013 excludes net losses of $(903) thousand allocable to the redeemable noncontrolling interest. See Note 8 - Redeemable Noncontrolling Interest.

[2] Other comprehensive loss, net of tax for the six months ended February 28, 2013 excludes $(1) million relating to foreign currency translation adjustments for the redeemable noncontrolling interest. See Note 8 - Redeemable Noncontrolling Interest.